Seal for crevices in oil-tank roofs and the like



L. A. BALDWIN SEAL FOR CREVICES IN OIL TANK ROOFS AND THE- LIKE Sept. 14 1926. v 1,599,549

Filed Sept. 3', 1925 Patented Sept, 14, 1 926.

UNITED STATES PATENT OFFICE.

LESLIE A. BALDWIN, OF CHICAGO, ILLINOIS, ASSIGNOR T JOHNS-MANVILLE INCOR PORA'IED, OF NEW YORK, N. Y.,

A CORPORATION OF NEW YORK.

SEAL ron canvrcns IN OIL-TANK aoors AND THE LIKE.

O Application filed September 3, 1925. Serial No. 54,236.

This invention relates to the construction of seals over crevices in roofs and particularly in the roofs or coverings of oil storage tanks where thorough precautions should be I taken in the interest of economy to render the tank roofs vapor-tight. Not infrequently cementitious sealing materials which are resistant to attack by hydrocarbons such as the vapors which generally accumulate 10 in oil storage tanks, are deteriorable by water, especially if water or water vapor is concentrated at any restricted region in the cementitious material. Frequently water vapors develop or are present in and mixed with the gases accumulated under the roof of a gas tank, and if any seam or crevice in a tank roof is not itself vapor-tight, this water vapor is liable to pass through the seam or crevice and attack protective cementitious material, locally extending or dissolving it with danger of producing a rupture in the seal itself which would then permit the passage not only of water vapor but of the hydrocarbon vapors which it is desired to confine and conserve. Particularly is this true of seam sealing materials such as silicate of soda or the more elastic and reliable pellicle-forming and seam sealing cement composed essentlally ofglue-glycer- 30 inc composition, gdescribed in an application filed by me erial No. 54,235) which, while unsusceptible to attack by substances such as hydrocarbon vapors, are distinctly deteriorable with respect to their sealing properties, by water. The improved seal for crevices or seams which provides against rupture by the action of water, and which constitutes my invention, is illustrated by example in the drawing hereto annexed.

Taking, for example, the preferred seal ing pellicle which comprises or chiefly consists of a glue-glycerine composition substantially solid at all climatic temperatures and characterized by sufficient elasticity to maintain continuity in spite of expansion and contraction of the roof, in the construction of the improved seal I .first thoroughly clean the upper surfaces of the tank roof plates represented by 1 and 2, at and near the crevice or seam therein which is to be sealed, as for instance at or near one of the lappedjoints secured at intervals by rivets such as at 3. Then I flow, while hot, a layer 40f the said vapor-tight composition upon the roof plates covering the lapped joint and apply the sealing material in such quantity that it forms a band or zone about ten inches wide. Ilhe sealing material should extend at least about as far from the rivets on one side as it does from the exposed lapped joint on the other, and the ground layer may be part of :a sealing pellicle extending integrally over the entire roof. While the sealing ground layer 4 is still warm and tacky I lay thereon strips of a bibulous felted material, such as a red rosin slzed. paper; these strips 'being not wide enough to cover the entire layer 4. If, for instance, the layer 4 has been laid about ten inches wide, 'the felted material 5 may be eight inches wide. Next'I flow over the bibulous felt and ground layer 4 of cement a third layer 6 of the same cementitious material, and, by preference, still another layer 7 on top of the layer 6 after the latter has wholly or partially set. The covering layers 6 and 7 are ofsuch'width as to extend over and cover the edges of the felted material 5 If water vapor should seep through the sealed seam, for instance at the point marked 8, since the cen'mentitious material and the water vapor are mutually miscible, the cementitious material at this localized region 8 will become so aflected as to endanger the tightness of the seal, were it not for the qualities of the bibulous felted strip 5 which come into play by absorbing the water condensed from the vapor and then'by capillary action spreading it laterally away from its region of initial concentration. When thus spread and distributed its extension renders any intermixture with the cementitious sealing material, on either side of the bibu-,

lous strip 5, entirely harmless, and indeed may render it somewhat beneficial in that a slight dampening of the elastic cementitious material tends to keep'it in good live and elastic condition. The bibulous felt layer thus functions to withdraw water from concentration in the ground layer 4 and prevent it from going directly through the clastic cement which it would be liable to do if the protective layer of felt were not present. I have found that if the seam-covering layers of elastic cementitious material are of such consistency when poured as to form each a layer of aboufthree-sixty-fourths of an inch thick, and if a red rosin sized bibulous material about one-sixteenth inch thick be laid as above described, the seal will successfully perform its protective function in the manner above described.

I claim:

1. A seal for crevices in oil'tank roofs and the like, comprising an inner layer of cementitious material miscible with water, a layer thereon of bibulous materiahand an outer layer of cementitious material covering the layer of bibulous material.

2. A seal for crevices in oil tank roofs and the like, comprising an inner layer of colloidal cementitious material miscible with water, a layer thereon of bibulous material, and an outer layer of cementitious material covering the layer of bibulous material.

3. A seal for crevices in oil tank roofs and LESLIE AJBALDWIIN. 

